I wouldn't worry about SketchUp Make disappearing. At least not for a long while. SketchUp for Web (SketchUp Free) has a little way to go before it would be a real replacement for Make. They keep adding features to it and it's always improving. There are a couple of benefits to the browser based version that make it appealing even if you are using SketchUp Make already. Since it runs in your browser, you can run it on devices like Chromebooks or on Linux machines. If you upload your models to Trimble Connect or the 3D Warehouse, you can access them from any computer. That means that even if you don't have SketchUp installed on your notebook, I can access and show you my models in the Wifi-equipped pub while you're buying me a pint. Every time you open SketchUp Free you are getting the latest version. Sometimes they pushtwo or three updates a week. Can you imagine downloading and updating SketchUp Make two or three times a week?

For those who want to use SketchUp for more than hobby use, there's now SketchUp Shop which is also browser based but has much more functionality than SketchUp Free. It is a subscription thing so for about $120/year, you have SketchUp anywhere you have Wifi access.

FWIW, once you have SketchUp Free or SketchUp Shop opened, it uses very little in internet resources unless you are downloading or uploading to/from the 3D Warehouse or Trimble Connect.